Nonhazardous polymerization initiators

ABSTRACT

ALCOHOLS BOILING BETWEEN 130-255*C ARE DISCLOSED AS EFFECTIVE PHLEGMARTIZERS IN SUPPRESSING THE EXPLOSIVE DECOMPOSITION OF KETONE PEROXIDES DUE TO HEATING.

XR 3557009 Ex ABSTRACT OF THE DISCLOSURE Alcohols boiling between 130-255 C." are disclosed as effective phlegmatizers in suppressing'the explosive decomposition of ketone peroxides due to heating.

'lhisinvention relates to new nonhazardous polymerization initiator compositions.

It is "an object of this invention to provide ketone peroxide epmpositions that are free from the explosive decomposition that ketone peroxides normally exhibit when heated 'to high temperatures.

It is.janother object of this invention to provide iretone peroxide compositions that have good storage stability, and are etlicient initiators for the polymerization of ethylenically unsaturated compounds.

Ketone peroxides are used extensively for the initiation of polymerization of ethylenically unsaturated compounds and their use is well known injhe art. While thermal initiation is often employed they have found their most extensive use in the so called room temperature polym'erizations employing a soluble sicaitive metal salt such as cobalt octoate, with the "unsaturated polyester resin. These resins are composed of an unsaturated alkyd resin dissolved in a monomer such as styrene or methyl methacrylate.

A wide range of ketone peroxides have been employed but the most common ones have been;prepared from methyl' ethyl ketone, cyclohexanone methyl amyl ketone; The hazardous nature of organic peroxides in general. and ketone peroxides in particular is well known in the art. The ketone peroxides prepared from the higher molecular weight ketone such as methyl amyl ketone, in which Ithe active oxygen content is lower, do not require diluents in order to be handled with reasonable safety. The peroxides prepared from the lower molecular weightj ketones in which the active oxygen content is higherrequire diluents for safe handling. The most commonly-employed diluents are dimethyl phthalate and dibutyl phthalate. The active oxygen concentration is usually adjusted to around 11%. While these diluents provide reasonable safety for ordinary handling, even materials diluted to 11% active oxygen qa'ncentration may decompose explosively when held at'high temperatures for a prolonged period of time.

The ketone peroxide in widest general use at the present time is methyl ethyl lretone peroxide. The commercial material is commonly marked as a 60% solution in dimethyl phthalate with an active oxygen concentration of 11%. Cyclohexanone peroxide is marketed as an 85% paste or moist solid with dibutyl phthalate as the diluent and an active oxygen concentration of 11%. Cyclohexanone peroxide is also marketed as a solution in combination with methyl ethyl ketone peroxide employing dimethyl phthalate as the diluent at an active oxygen concentration of 11%. v

A composition can be obtained by sufficient dilution of the ketone peroxide with dimethyl phthalate that does not exhibit explosive decomposition even when ice boiled to dryness. The dilute solutions however have not found general acceptance because of the added expense of the diluent, the resulting higher freight and container cost and the desire to minimize the amount of inactive 5 diluent in many formulations.

The term nonhazardous as used herein encompasses primarily suppression of the rapid decomposition exhibited by ketone peroxides when heated to high temperatures which results in ex losions or detonations even when unconfined. It is understood that some of the compositions that are nonhazardous by this definition may burn readily or even accelerate during burning as do most organic peroxides.

The term phlegmatizer is used in explosive technology to describe materials or compounds that desensitize or stabilize. While the diluents commonly employed with ketone peroxides can properly be classed as phlegmatiz ers for simplification, the term is reserved herein to refer exclusively to the suppression of the explosive decomposition'of these materials.

The term ketone peroxide as used herein is used in the common sense and refers to the monomers or open chain polymers of the hydroxy-hydroperoxides or dihydroxy peroxides which are formed from ketones and hydrogen peroxides and which are in general commercial use. It is not intended to include the cyclic-polymeric ketone peroxides which do not readily undergo redox decomposition with soluble salts of sicative metals which do not have general application as polymerization initiators 3 and in many cases are highly explosive in nature. In

audition to the ketone peroxide and diluent, small amounts of water and hydrogen peroxide are often present.

It has been discovered in accordance with the present invention that alcohols are effective phlegmatizers or desensitizer for ketone peroxides and suppress the rapid accelerating decomposition that results in explosions when these peroxides are heated to high temperatures. It has been further discovered that not all alcohols are active and that the effectiveness of the alcohol is related to the boiling point. Thus relatively small concentrations of an alcohol with a boiling point in the optimum part of the range is effective while much larger concentrations are required with alcohols boiling near the edges of the range.

The alcohols were found to be efiective in suppressing explosive decomposition even in low concentrations was rather surprising since water not only is ineffective in small concentrations but in some instances increases the violence of the decomposition. Hydrogen peroxide likewise was found to increase the violence of the decomposition.

Nonflammability of the diluent is not a major factor in suppressing explosive decomposition since highly halogenated compounds were not observed to contribute to the explosive stability of ketone peroxide systems.

Ethers were not-found to be efifective. The only compounds in both ghoups that exhibited any stabilizing action at all boiled 'in the l70175 C. range further substantiating the importance of the boiling point.

The alkoxyor alkylpolyoxyethylene alcohols are less eilicient than the aliphatic alcohols, but the ketoalcohols are highly efficient in suppressing explosive decomposition.

Alcohols boiling in the range of 130-255 C. are effective in suppressing explosive decomposition but the range 140-205 C. is particularly eifective with an optimum eliectiveness between 150-190 C. The loss of activity of an alcohol falls 06 quite rapidly at the. lower boiling point range but diminishes slowly at the higher boiling point range. There is some variations in phlegmatizing activity with structure but it is not a major factor compared to the boiling point of the alcohol.

As stated before the requirements for a nonhazardous composition depend on three parameters; the concentration of the ketone peroxide, the concentration of the alcohol and the boiling point of the alcohol. Thus in the edges of the effective boiling point range all of the diluent would be alcohol in order to give a nonhazardous composition at an active oxygen concentration of 11% while in the optimum part of the range an alcohol concentration of only 10% of the total composition is effective at the same active oxygen content. On the other hand employing such an alcohol as the entire diluent the active oxygen concentration can be increased above 11% to 14% Alcohols boiling in the 130-255 range are effective phlegmatizers with ketone peroxide compositions containing hydrogen peroxide even though hydrogen peroxide increases the violence of decomposition of ketone peroxide compositions employing dimethyl phthalate alone as the diluent.

A considerable range of hydrogen peroxide concentrations can be employed safely but is limited due to the adverse effect of large concentration on the efliciency of the composition as a polymerization initiator.

The storage stability of ketone peroxide compositions containing alcohols varies depending on the structure of the particular alcohol employed but are comparable to those in commercial use.

The influence of the alcohol on the eifectiveness of the compositions as polymerization initiators varies with the resin or monomer employed and the promotor and inhibitor system they contain. These are variations that are well understood in the art and exist in current commercial formulations.

EXAMPLE 1 The typical tmsaturated polyester resin," or, polyester resin, as they are commonly called in the trade, used in the following examples was prepared as follows: 65 parts alkyd resin, acid No. 45-50 prepared from 1 mole maleic anhydride, 1 mole phthalic anhydride and 2.2 moles propylene glycol, plus 35 parts styrene, 0.13 part hydroquinone and 0.03 part of cobalt as cobalt octoate.

EXAMPLE 2 The term PVT Test in the examples, refers to a pressure vessel test developed in Holland by Dr. E. W. Lindeijer at the Technological Laboratory of the National Defense Research Organization and work with it in this country is described by O. T. Mageli et al. Ind. Eng. Chem. 56, 18 (1964). It consists essentially of a pressure vessel into which a sample is placed in a standard metal cup. On top is fitted a burst diaphragm calibrated for 100 p.s.i. On the side is a fitting into which discs having varying apertures can be inserted. Using a standard heating rate, the smallest aperture that can be tolerated without rupture of the burst diaphragm is determined for a given compound. The smaller the aperture the less hazardous the compound.

EXAMPLE 3 The TCT Test in the following examples refers to a test developed by Mr. Howard Greer of Bel Air, Texas. It consists essentially of placing 100 ml. of the composition to be tested in a steel can similar to those used for frozen iuice, inserting a 250-watt immersion heater, and observing the results of heating to destruction. The sample may boil to dryness,-catch fire, pop, or explode violently depending on the composition. The can may be left standing intact or in violent explosion, completely disintegrate. It has been found to be at least as reproducible as the PVT Test. Like the latter it must be run under standardized conditions but is an efiective procedure for determining the behavior of peroxide compositions under severe conditions.

4 EXAMPLE 4 Preparation of ketone peroxides. Methyl ethyl ketone peroxide compositions were obtained by reacting g. methyl ethyl ketone, 159 g. of

50% hydrogen peroxide and 115 g. of the phlegmatizer in the presence of 1.5 g. of sulfuric at 55 C. for one hour.

The reaction product was dried over sodium sulfate, the unreacted methyl ethyl ketone removed by distillation. The desired concentration of methyl ethyl ketone peroxide composition was obtained by the addition of phlegmatizer.

EXAMPLE 5 Bolling point, Additive C. TOT test tert-Butyl alcohol 83 Explosion. tert-Pentyl alcohol 100-3 Do. l-butan 118 Do. zpentanol 119 Do. 3-methyl-1-butanol- 132 Do. 1-p6ntan 138 Do. Cyclo ntanol-.. 139-41 Do. a-ethy -3-pentano 143-4 Do l-hexanol 152-4 Fire only. 3-he tanol... 155-7 Mild ex losion. Cyc ohexanol -2 Fire on y. 2-methyl-2-hegtanol 162 Do. Furiuryl alco 01.... -3 Do.- tanol 177-8 Do. 2,6-dimethyld-heptanoL. 178-9 Do; thyl-lexanol 184-91 Do. 3,4-dimenhyicyclohexano -2 Do. Benzyl ho 205 Do. l-decanol- 217-22 Mild explosion. l-dodecanol... 255 Do. Water 100 Explosion. Hfigrogen peroxide (25% Do. D ethyl phthalate 282 Do.

I EXAMPLE 6 The following compounds were tested as described in Example 5.

Boiling l point. Additive C. TCT test S-methory-l-butanol 155-64 Mild explosion. Diprop leneglycol monornethylether 187 Do. fl-lsobu xyethanol 280 Do. 1-(8-buwxyethoxy)-2-propanol 230 Do. Diethyleneglyeol monobutylether- 231 Do. Diaoetone alcohol 164-6 Fire only.

. EXAMPLE 6A Methyl ethyl ketone peroxide, 45 Cyclohexanone peroxide, 17 Fire Dimethyl phthalate, 30 Z-ethyl-l-hexanol, 8

EXAMPLE 7 A series of methyl ethyl ketone peroxide compositions were tested by the TCT Test described in Example 3.

EXAMPLE 11 A ti i n ni t The following diluents were tested as described in Ex 001'] I1 D Diluent percent C. 'IG'I test ample B-methyl-l-butanol 11. 182 Mild explosion- I iii Cycioptintanol 39 Firel. 5 8013? DMD 0 2-ethyl-l-hexanol 14% 184-91 n3. Additive Toll-"est Halogenatbi compounds:

Bi 'o ln zgat lz ane. 40 Explgsion. EXAMPLE 8 rl t'mfinwmifiit n8: 10 Bromofbrm m0 .130. A series of compositions of methyl ethyl ketone perlflfil-tfiehloropropanenu 156 Do. oxide, dimethyl phthalate and 2 ethyl-l-hexanol were j gm f gflgg ggg 1;} gg enaluated by the PVT Test described in Example 2. This o-Dichlorobenzene.-.. 179-83 Explbsion. ilhistrates the relationship of concentration of Organic gglggggag giggggl mg peroxide, and alcohol on explosive decomposition. Ethers: e

Dionne 101 ExpFlon. Dibutyl ether 142 Y 0. "an ti 6 l ketoize Dlmethyl 2-ethyl-l- PVT test blgliei i yl ether 2:59 1252352. on peroxide phthalatet, hexanolt, ii mm. oripereen percen pereen ee 60 4o 0 v m 20 EXAMPLE l2 8 88 g 2 gg Sample of the compositions listed were stored at 110 F. g :2 2 6 P for a period of 30 days and the decrease in active oxygen B8888 w 12 28 Do content determined. g g 32 Do.

t 51 1 533.23 49.4 50.6 L; Start, days, 4s 5 51. 5 1

1. es th 1 ht 1k 1 5&7 35.5 40.8 rfi ls 30 23 E 121131 hthzl gt i 55 33. 75 11. 25 Passes 0 methyl ethyl ketone peroxide 53.4 as 11.6 Do. a0.47 dimethyl phthalate I 12.5% myl-l-hexanol 7 6 4.1% 60%31ydrogen peroxide EXAMPLE 9 EXAMPLE 13 35 A series of compositions of methyl ethyl ketone per-' I oxide, dimcthyl phthalaw, 2 cthybbhexanol, hydrogen The polymenzation initiation characteristics of sevperoxide and water were evaluated by the PVT Test of 3 methyl ethyl'ketone P formulatlons f f Example 2. The results illustrate the relation of concenalwhols as P F f were determmed m tration of ketone peroxide versus alcohol in compositions 40 standard P E of Example 1% of the containing water and hydrogen peroxide on explosive depel'oxldc fofmulatlon was composition.

o lti ti e me, me i ethyl Dim th 1 nth 11 h d i test mimms minutes ne 8 y y to en peroxide, phthalatet, hexanhlt, peroxida, wat r 4:11am. 4 fi l i g gfigfi 2 n8 p Demen Dewen p Percen 0 0e cycbhemnol m 41 Hthyl-l-hexanol 0 123 41 3-ethyl-3-pentanoL 51 141 41 Cyclopentan 51 143 m 5 m 5 3, 'l-dimethfl-S-oflanol 58 188. 9 30 10 25 50 -dodeoano 62 202. 4 3 1;? hfithll-giilhate 36 114 g 4 3 Cycl'ohexanol. 34 121 3 4 mi-hu or B8 121 41, 5 4'6 Form 1 additive: 40 g Cyelohexanol 35 96. 5 5 5 55 Thefiime in minutes from gel to a reading 0! 10 on the medium scale Bercol Impressometer. Fermi-11a A: g. of methyl ethyl ketone peroxide in dimethyl phthalate. Active oxy on content 11.6% plus 10 g. ot additive. EXAMPLE 10 5 FognfilalhBidi g. orme g l eithyllfiketope d t( 1!id9 m Forgnula A plus .o y enperox e us .0 a rive. =1, Th tests f E l 9 are {unh d d employing fi ormnla O: 1% g. of methy ethyl ketone peroxide as lnFormula A 1 1 i TCT Test of Example 3 and expanded to include cyclo- 60 pm omhydmgen peroxide plum ofaddmve hexanol and a wider variation in the concentration of hywe dam: dmgen pemxida A nonhazardous ketone peroxide composition consistmg essentially of methyl ethyl ketone peroxide in sufficient quantity to give 8.2 to 14.5% active oxygen conh %fig: Hum- 5 tent to said composition, not more than about 7.5% wair i g i' t gyl g ide M e:- h Cy clop gm TCT mt ter; not more than about 40% phthalate ester plasticizer; p g. mo 3. exam ,x- 8 8- from about 4.5 to 41% of a keto-alcohol boiling between and 190 C.

2. The composition of claim 1 wherein the keto-al- 70 cohol is diacetone alcohol.

3. Anonhazardous methyl ethyl ketone peroxide cornpositien consisting essentially of 40 to 76% methyl ethyl 'ketone peroxide, 1 to 7.5% hydrogen peroxide, 1 to 7.5% of water, 4.5 to 41% of an-alcohol boiling between 75 and C., 0 to 40% of a phthalate ester plasticizer in 7 which the active oxygen content does not exceed 14.5% and the alcohol concentration increases with active oxygen concentration.

4. The claim of claim 3 in which the alcohol is cyclohexanol.

s. The claim of claim a in which the alcohol is 2- 5 ethyl- 1 -hcxanol.

6. The claim of claim 3 in which the alcohol is furfuryl alcohol.

7. The claim of claim 3 in which the alcohol is 2-octan01.

8. The claim of claim 3 in which the alcohol is Z-methyI-Z-heptanol.

References Cited UNITED STATES PATENTS 10/1939 Milas 2606l0 7/1967 Mageli et a1. 26061O RICHARD D. LOVERING, Primary Examiner I. GLUCK, Assistant Examiner US. Cl. X.R. 

